``Dal-``(달-) has been a simple word and also a base of derived verbs ``dari-``(다리-), ``dalgu-``(달구-), ``dalhoi-``(달호이-) and so on since the 15th century. ``Dal-``(달-) has meant ``heat up`` since the 15th century in Korean. ``Dal-``(달-) is used with [+solid], [+liquid] and abstract nouns. ``Dari-``(다리-) showed up since the 15th century is analysed into a base ``dal-``(달-) and causative suffix ``-i-``(-이-). ``Dari-``(다리-) was used with [+liquid] or [+solid]. When ``Dari-``(다리-) was used with [+solid], it meant ``iron``. And there was ``dalhi-``(달히-) in the 15th century. There were derived verbs analysed into a base ``dal-``(달-) and causative suffix ``-Xo/Xu-`` in the 15th century. Those verbs were ``dal-o-/dal-u-/dalgu-/dalho-``(달오-/달우-/달구-/달호-). These verbs were used with [+solid], especially ``metal``. There were derived verbs analysed into a base ``dal-``(달-) and causative suffix ``-Xo/Xu-`` and passive suffix ``-i-`` in the 18th and 19th century. Those verbs were ``dal-ho-i-/dalhoi-``(달호이-/달회-). These verbs were used with ``body`` or ``face``, and meant ``flush``.